US20050053485A1 - Sealed type motorized compressor and refrigerating device - Google Patents
Sealed type motorized compressor and refrigerating device Download PDFInfo
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- US20050053485A1 US20050053485A1 US10/498,476 US49847604A US2005053485A1 US 20050053485 A1 US20050053485 A1 US 20050053485A1 US 49847604 A US49847604 A US 49847604A US 2005053485 A1 US2005053485 A1 US 2005053485A1
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- sealed container
- electric compressor
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- 230000006835 compression Effects 0.000 claims abstract description 75
- 238000007906 compression Methods 0.000 claims abstract description 75
- 239000003507 refrigerant Substances 0.000 claims description 23
- 238000005057 refrigeration Methods 0.000 claims description 12
- 239000004215 Carbon black (E152) Substances 0.000 claims description 3
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims description 3
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 claims description 3
- 229910052801 chlorine Inorganic materials 0.000 claims description 3
- 239000000460 chlorine Substances 0.000 claims description 3
- 229910052731 fluorine Inorganic materials 0.000 claims description 3
- 239000011737 fluorine Substances 0.000 claims description 3
- 229930195733 hydrocarbon Natural products 0.000 claims description 3
- 150000002430 hydrocarbons Chemical class 0.000 claims description 3
- 238000013461 design Methods 0.000 description 10
- 230000001133 acceleration Effects 0.000 description 9
- 230000004048 modification Effects 0.000 description 6
- 238000012986 modification Methods 0.000 description 6
- 230000002238 attenuated effect Effects 0.000 description 4
- 238000010009 beating Methods 0.000 description 4
- 238000013459 approach Methods 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 230000002159 abnormal effect Effects 0.000 description 2
- 238000006073 displacement reaction Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 230000000644 propagated effect Effects 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000004804 winding Methods 0.000 description 2
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000003292 diminished effect Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
Images
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B39/00—Component parts, details, or accessories, of pumps or pumping systems specially adapted for elastic fluids, not otherwise provided for in, or of interest apart from, groups F04B25/00 - F04B37/00
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B39/00—Component parts, details, or accessories, of pumps or pumping systems specially adapted for elastic fluids, not otherwise provided for in, or of interest apart from, groups F04B25/00 - F04B37/00
- F04B39/12—Casings; Cylinders; Cylinder heads; Fluid connections
- F04B39/127—Mounting of a cylinder block in a casing
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B39/00—Component parts, details, or accessories, of pumps or pumping systems specially adapted for elastic fluids, not otherwise provided for in, or of interest apart from, groups F04B25/00 - F04B37/00
- F04B39/0027—Pulsation and noise damping means
- F04B39/0044—Pulsation and noise damping means with vibration damping supports
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B39/00—Component parts, details, or accessories, of pumps or pumping systems specially adapted for elastic fluids, not otherwise provided for in, or of interest apart from, groups F04B25/00 - F04B37/00
- F04B39/12—Casings; Cylinders; Cylinder heads; Fluid connections
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B39/00—Component parts, details, or accessories, of pumps or pumping systems specially adapted for elastic fluids, not otherwise provided for in, or of interest apart from, groups F04B25/00 - F04B37/00
- F04B39/12—Casings; Cylinders; Cylinder heads; Fluid connections
- F04B39/121—Casings
Definitions
- the present invention relates to a hermetic electric compressor for building a refrigeration unit of refrigerator, automatic vending machine and the like apparatus.
- FIG. 12 shows the conventional hermetic electric compressor, sectioned vertically, which is referred to in the patent document 1 .
- sealed container 1 houses electric compression element 2 and coil spring 3 ; there is space 4 as well in the container.
- Coil spring 3 is engaged at both ends by snubber 5 protruding from electric compression element 2 side and sealed container 1 side; namely, electric compression element 2 is elastically supported by coil spring 3 .
- the hermetic electric compressor has been designed to compress the R134a refrigerant, a typical HFC system refrigerant, whose ozone layer destruction factor is zero.
- FIG. 13 is noise characteristic chart of the conventional hermetic electric compressor, disclosed in the patent document 1; the lateral axis representing the 1 ⁇ 3 octave frequency, the longitudinal axis the noise level.
- FIG. 14 details the noise characteristic shown in FIG. 13 ; where, the lateral axis representing the frequency, the longitudinal axis the noise level.
- FIG. 15 shows resonance frequency characteristic of mechanical vibration generated by electric compression element 2 of the conventional hermetic electric compressor; the lateral axis representing the frequency, the longitudinal axis representing level of the acceleration.
- the natural resonance frequency due to mechanical vibration generated by electric compression element 2 has been measured by running without load a hermetic electric compressor with the power supply frequency varied, and plotting the acceleration level measured on electric compression element 2 , on the frequency axis.
- the resonance frequency due to mechanical vibration caused by electric compression element 2 is defined as a range of frequencies where the measured acceleration level (vibration level) reach the highest, including the foot areas of the peak in the higher and the lower frequency regions.
- FIG. 16 shows resonance frequency characteristic of coil spring 3 , in the state where electric compression element 2 is put on coil spring 3 ; the lateral axis representing the frequency, the longitudinal axis representing the acceleration level. Also shown in the chart is a cavity resonance frequency formed in space 4 , with R134a used as the refrigerant.
- the natural resonance frequency of coil spring 3 has been measured by running without load a hermetic electric compressor with the power supply frequency varied, and plotting the acceleration level measured on the surface of sealed container 1 , on the frequency axis.
- the resonance frequency of coil spring 3 is defined as the range of frequencies where the measured acceleration level (vibration level) reaches the highest, including the foot areas of the peak in the higher and the lower frequency regions.
- electric compression element 2 When power supply is turned ON, electric compression element 2 starts its operation of compressing refrigerant gas. Due to changes of loads and other factors during the compression operation, electric compression element 2 generates mechanical vibrations which contain various frequencies. The mechanical vibration should cause big noises and vibrations if it is conveyed direct to sealed container 1 . However, since the elasticity of coil spring 3 absorbs vibration, the vibration which should have been conveyed to sealed container 1 is attenuated. Thus the noises and vibrations are reduced with the hermetic electric compressors.
- peak of resonance frequency of the mechanical vibration generated by electric compression element 2 resides at the neighborhood of 540 Hz, which approximately coincides with the peak of resonance frequency of coil spring 3 mounted with electric compression element 2 . Since resonance frequency of the mechanical vibration and that of coil spring 3 are in coincidence, the hermetic electric compressor exhibits a noise peak at 540 Hz, as shown in FIG. 14 .
- cavity resonance frequency formed in space 4 within sealed container 1 resides somewhere at the peak, inclusive of its foot areas, of resonance frequency of coil spring 3 mounted with electric compression element 2 .
- peak of the resonance frequency of coil spring 3 mounted with electric compression element 2 resides at the vicinity of 550 Hz. Also the cavity resonance frequency formed in space 4 approximately coincides with the frequency. Furthermore, the hermetic electric compressor has its noise peak in the neighborhood of 550 Hz, as shown in FIG. 14 .
- the reason for the above is as follows.
- the mechanical vibration generated by electric compression element 2 vibrates coil spring 3 via upper snubber 5 .
- the beating and rubbing is applied on coil spring 3 as vibration energy.
- coil spring 3 resonates at the inherent resonance frequency of coil spring 3 mounted with electric compression element 2 .
- noise is generated at the frequency, and the noise vibrates a cavity formed in space 4 of sealed container at the resonance frequency.
- the noise with hermetic electric compressors is enhanced.
- cavity resonance frequency formed in space 4 of sealed container 1 coincides with the peak, including the foot areas, of resonance frequency of mechanical vibration generated by electric compression element 2 and resonance frequency of coil spring 3 , resonation of coil spring 3 created by the mechanical vibration provides a vibrating effects on space 4 .
- the noise due to resonation of the cavity is further increased with the conventional hermetic electric compressors.
- the present invention offers a hermetic electric compressor which includes a sealed container and a coil spring for elastically supporting an electric compression element housed within the sealed container.
- resonance frequency of the coil spring mounted with the electric compression element does not coincide with resonance frequency of mechanical vibration caused by the electric compression element, or a cavity resonance frequency formed in a space within the sealed container.
- FIG. 1 is a cross sectional view of a hermetic electric compressor in accordance with a first exemplary embodiment of the present invention, sectioned vertically.
- FIG. 2 shows a front elevation of a coil spring in the first embodiment.
- FIG. 3 is a resonance frequency characteristic chart of a coil spring in the first embodiment.
- FIG. 4 is a noise characteristic chart, which compares a hermetic electric compressor in the first embodiment and a conventional hermetic electric compressor.
- FIG. 5 is a detailed noise characteristic chart of a closed-type electric compressor in the first embodiment.
- FIG. 6 shows a cross sectional view of a hermetic electric compressor in accordance with a second exemplary embodiment of the present invention.
- FIG. 7 is a resonance frequency characteristic chart of a coil spring used in a hermetic electric compressor in accordance with the second embodiment.
- FIG. 8 is a noise characteristic chart of a hermetic electric compressor in the second embodiment.
- FIG. 9 is a magnified view of a snubber and a coil spring in accordance with a third exemplary embodiment of the present invention.
- FIG. 10 is a resonance frequency chart, used to show how change in the resonance frequency is caused with a coil spring in the third embodiment.
- FIG. 11 shows how a refrigeration unit in accordance with a fourth exemplary embodiment of the present invention is structured.
- FIG. 12 shows a cross sectional view of a conventional hermetic electric compressor, sectioned vertically.
- FIG. 13 is a noise characteristic chart of a conventional hermetic electric compressor.
- FIG. 14 is a detailed noise characteristic chart of a conventional hermetic electric compressor.
- FIG. 15 is a resonance frequency characteristic chart, showing a resonance created by mechanical vibration caused by electric compression element in a conventional hermetic electric compressor.
- FIG. 16 is a resonance frequency characteristic chart of a conventional coil spring.
- FIG. 1 shows a cross sectional view, vertically sectioned, of a hermetic electric compressor in accordance with a first exemplary embodiment.
- FIG. 2 shows a front elevation of a coil spring in the first embodiment.
- FIG. 3 is a resonance frequency characteristic chart of coil spring 101 mounted with electric compression element 2 in the first embodiment; the lateral axis representing frequency, while the longitudinal axis representing acceleration level. Cavity resonance frequency formed in space 4 is also shown, with two examples where R600a and R134a, respectively, are used as the refrigerant.
- FIG. 4 compares a hermetic electric compressor in the first embodiment and a conventional hermetic electric compressor in the noise characteristic; the lateral axis representing 1 ⁇ 3 octave frequency, while the longitudinal axis representing noise level.
- Dotted line indicates a hermetic electric compressor in the first embodiment
- solid line indicates a conventional hermetic compressor.
- FIG. 5 shows details of the noise characteristic in the first embodiment shown in FIG. 4 ; the lateral axis representing frequency, while the longitudinal axis representing noise level.
- sealed container 1 houses electric compression element 2 and coil spring 101 , and is provided with space 4 in the inside. At both ends of coil spring 101 are snubbers 5 inserted thereto; each of the snubbers protruding from electric compression element 2 and sealed container 1 , respectively. Thus, electric compression element 2 is elastically supported by coil spring 101 .
- the pitch of coil spring 101 in the first embodiment is uneven, as shown in FIG. 2 . It has a wider pitch “a” at the both end portions, and gradually gets narrower to become a narrow pitch “b” at the central portion; namely, it is wound in a coarse pitch at both end portions and the winding gets denser at the central portion, so coil spring 101 is top-bottom symmetry with respect to the center.
- a hermetic electric compressor in the first embodiment has been designed for compressing R600a, a representative refrigerant of hydrocarbon system, which is free of chlorine, fluorine, and the global-warming factor is zero.
- electric compression element 2 When power supply is turned ON, electric compression element 2 starts compressing the refrigerant. As a result of compressing operation, electric compression element 2 causes mechanical vibrations of various frequencies. The level of vibration goes high at the neighborhood of 540 Hz among other frequencies, or the peak resonance frequency with the mechanical vibration.
- the resonance frequency of coil spring 101 mounted with electric compression element 2 resides at the neighborhood of 470 Hz, where acceleration level (vibration level) of the mechanical vibration is low. Thus it is not in coincidence with the resonance frequency of mechanical vibration caused by electric compression element 2 . So, coil spring 101 is not driven by the mechanical vibration to create a resonance. Thus, vibration due to resonation of coil spring 101 hardly occurs, and noises and vibrations are reduced with a closed-type electric compressor.
- sonic velocity in the first embodiment is higher as compared with that when R134a refrigerant is used.
- a cavity resonance frequency formed in space 4 of sealed container 1 shifts high to the neighborhood of 700 Hz, from the neighborhood of 540 Hz.
- the sonic velocity with a refrigerant gas changes also in accordance with a change in the temperature or the pressure of the refrigerant, as indicated in (formula 1); and the resultant shift in the cavity resonance frequency is normally several tens of Hz. So, even after the shift in resonance frequency is taken place, the peak, inclusive of the foot areas, of coil spring 101 's resonance frequency is residing sufficiently away from the cavity resonance frequency, as seen in FIG. 3 .
- f 1 K ⁇ V L ⁇ ( K : constant ) ( formula ⁇ ⁇ 1 )
- a vibration due to resonation of coil spring 101 hardly occurs, and a gaseous column formed in space 4 of sealed container is hardly put into resonation. Thus, resonating sound of cavity is reduced. Therefore, the noise can be further lowered with a hermetic electric compressor.
- pitch a: pitch b (1.09-1.60):1.
- peak level of coil spring 101 's resonance frequency has been lowered, while the elastic modulus was kept at the comparable level as that of conventional even-pitched coil spring 3 .
- the value of pitch a against pitch b is in excess of 1.60, the difference of spring constant within coil spring 101 becomes too large, and the amount of displacement grows big in the neighborhood of pitch b, where the spring constant is small. So, there would be a possibility that the spring wires get in direct contact to each other at the neighborhood of pitch b, and coil spring 101 would get broken due to vibration of compressor or other factors.
- the value of pitch a against pitch b is smaller than 1.09, uneven-pitched coil spring 101 's advantage in the noise reduction is diminished in relation to even-pitched coil spring 3 .
- the coincidence in resonance frequency with a cavity formed in space 4 of sealed container 1 can be avoided through a simple modification of coil spring 101 alone.
- the low noise-level design can be implemented easily.
- the resonance frequency of coil spring 101 can be lowered by either making wire diameter d smaller, increasing effective number of turns Na or increasing inner diameter D.
- this invites a lowered elastic modulus.
- coil spring 101 shrinks a great deal due to the weight of electric compression element 2 , which leads to an unwanted mechanical contact of electric compression element 2 with sealed container 1 and generation of abnormal sounds.
- the wire diameter d is thinned, stress increases to a deteriorated reliability.
- the effective number of turns Na is increased, total length of coil spring 101 increases, which leads to an increased overall height of sealed container 1 , and a problem of oversized hermetic electric compressor arises.
- coil spring 101 's resonance frequency is to be made higher, wire diameter d may be increased, effective number of turns Na may be decreased or inner diameter D may be made to be smaller.
- this invites an increased elastic modulus, so the amount of mechanical vibration generated by electric compression element 2 that can be absorbed by the coil spring decreases, while the amount of vibration conveyed to sealed container 1 increases, which creates a problem of increased noises and vibrations with a hermetic electric compressor.
- uneven-pitched coil spring 101 used in the first embodiment can lower the resonance frequency without sacrificing the elastic modulus and the reliability. Therefore, the problem of abnormal sounds due to mechanical contact between electric compression element 2 and sealed container 1 caused by a lowered elastic modulus and the problem of a deteriorated reliability due to the increased stress are avoidable.
- the problem of oversized hermetic electric compressor due to the increased length of coil spring 101 can also be avoided.
- the problem of increasing noises and vibrations with a hermetic electric compressor due to the increased elastic modulus of coil spring 101 can be avoided either.
- coil spring 101 has been wound to have a top-bottom symmetry in the coiling pitch, the operation of coupling with snubber 5 can be performed regardless of the top-bottom orientation of coil spring 101 . This is another advantage in the assembly of hermetic electric compressors.
- FIG. 6 shows cross sectional view of a hermetic electric compressor in accordance with a second exemplary embodiment.
- coil spring 24 in the second embodiment has a lowered elastic modulus.
- FIG. 7 is a resonance frequency characteristic chart of coil spring 24 mounted with electric compression element 2 of a hermetic electric compressor in accordance with second embodiment; the lateral axis representing frequency, while the longitudinal axis representing acceleration level. A cavity resonance frequency formed in space 4 is also shown in the chart.
- FIG. 8 shows measured noise level of a hermetic electric compressor in the second embodiment; the lateral axis representing frequency, while the longitudinal axis representing noise level.
- sealed container 1 houses electric compression element 2 and coil spring 24 , and is provided with space 4 inside the container. At both ends of coil spring 24 are snubbers 5 inserted thereto; each of the snubbers is protruding from electric compression element 2 and sealed container 1 , respectively. Electric compression element 2 is thus supported elastically by coil spring 24 .
- a cavity resonance frequency formed in space 4 is inversely proportional to length L of space 4 of sealed container 1 , as exhibited in (formula 1).
- f 1 K ⁇ V L ⁇ ( K : constant ) ( formula ⁇ ⁇ 1 )
- FIG. 7 shows inherent resonance frequency of coil spring 24 mounted with electric compression element 2 .
- the chart has been provided by running without load the hermetic electric compressor varying the operation frequency, and plotting the vibration level measured on the surface of sealed container 1 on the frequency axis.
- Resonance frequency of coil spring 24 mounted with electric compression element 2 is defined, based on the results made available by the above measurement, as the range of peak frequency, where the vibration level reaches the highest, including the foot areas at both the higher and the lower frequency regions.
- the resonance frequency in the present example has the foot area of approximately 50 Hz in both the higher and the lower frequency regions.
- Sonic velocity with a refrigerant shifts depending on the changes in temperature and pressure, which shift affects the a cavity resonance frequency formed in space 4 of sealed container 1 .
- Resultant change in the resonance frequency is a fluctuation of several tens of Hz.
- coil spring 24 having a lowered elastic modulus is employed so that the peak of coil spring 24 's resonance frequency is raised to be higher than that of the cavity by approximately 200 Hz. Thereby, it would not coincide with a cavity resonance frequency.
- the noise is conveyed to space 4 of sealed container 1 .
- the peak frequency is higher by 200 Hz than cavity resonance frequency formed in space 4 , it is totally out of the scope of resonance frequency range including foot area of approximately 50 Hz existing in both the higher and the lower frequency regions, taking the fluctuation of several tens of Hz in the cavity resonance frequency into consideration. Therefore, the noise would not excite the cavity resonance, and travels along space 4 within sealed container 1 and reaches sealed container 1 after being attenuated.
- a cavity formed in space 4 of sealed container has no source of vibration for resonation, and a hermetic electric compressor of reduced cavity resonance sound is offered.
- coil spring 24 of lower elastic modulus is used for making the inherent resonance frequency of coil spring 24 mounted with electric compression element 2 to be different from a cavity's resonance frequency.
- coil spring 24 absorbs more amount of mechanical vibration caused by electric compression element 2 , as compared with a case where coil spring 24 of higher elastic modulus is used. So, the vibration conveyed to sealed container 1 is significantly attenuated, and vibrations and noises with a hermetic electric compressor are reduced further.
- the present invention offers a hermetic electric compressor whose vibration is low and the noise is also low.
- the coincidence in resonance frequency with a cavity formed in space 4 of sealed container 1 can be avoided through a simple modification of coil spring 24 alone.
- the low noise-level design can be implemented easily.
- hermetic electric compressor which employ sealed container 1 of different sizes, different kinds of refrigerant gas, different electric compression elements of different weights, etc.
- the structure of no-coincidence with a cavity resonance frequency formed in space 4 of sealed container 1 can be realized by simply changing coil spring 24 alone.
- a low-noise design can be implemented with ease in accordance with the present invention.
- FIG. 9 is a magnified cross sectional view of snubber 25 and coil spring 124 in a third exemplary embodiment.
- FIG. 10 is a resonance frequency characteristic chart, which shows results of measurement on relationship between contacting length of snubber 25 with inner diameter of coil spring 124 and the resonance frequency, and a cavity resonance frequency formed in space 4 within sealed container 1 ; the lateral axis representing contacting length of snubber 25 with inner diameter of coil spring 124 , the longitudinal axis representing resonance frequency.
- snubber 25 in the present third embodiment which is basically the same as that used in a hermetic electric compressor in the first embodiment, has a shorter length in its straight appearance portion 25 a, so that the length of snubber 25 having contact with inner diameter of coil spring 124 becomes shorter.
- the resonance frequency of coil spring 124 mounted with electric compression element 2 has been set at a point which is higher by 100 Hz than that of a cavity formed in space 4 of sealed container 1 , by reducing the contacting length of straight appearance portion 25 a with inner diameter of coil spring 124 .
- the coincidence of coil spring 124 's resonance frequency with that of a cavity formed in space 4 of sealed container 1 can be avoided through a simple modification of lower snubber 25 in its straight appearance portion 25 a alone.
- the cavity formed in space 4 of sealed container 1 has no source of vibration for resonation, and a hermetic electric compressor of low cavity resonance sound is offered.
- FIG. 11 shows a structure of a refrigeration unit in accordance with a fourth exemplary embodiment.
- compressor 11 condenser 12 , expansion device 13 , drier 14 and evaporator 15 are coupled by means of piping for allowing a fluid to circulate.
- a hermetic electric compressor in the present invention reduces the creation of a resonation by coincidence of coil spring resonance frequency and resonance frequency of mechanical vibration.
- a low-noise and low-vibration configuration is implemented for the hermetic electric compressors.
- a hermetic electric compressor in the present invention reduces the creation of a resonation by coincidence of coil spring resonance frequency and cavity resonance frequency formed in the space.
- a low-nose and low-vibration configuration is implemented for the hermetic electric compressors.
- the compressor can be used also in a refrigeration showcase, a dehumidifying apparatus, etc.
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Abstract
Description
- The present invention relates to a hermetic electric compressor for building a refrigeration unit of refrigerator, automatic vending machine and the like apparatus.
- There have been several models of hermetic electric compressors designed for low-vibration and low-noise application. (As for an example, refer to the
patent document 1, Japanese Patent No.2609713.) - A conventional hermetic electric compressor taught in the above document is described referring to drawings.
-
FIG. 12 shows the conventional hermetic electric compressor, sectioned vertically, which is referred to in thepatent document 1. Referring toFIG. 12 , sealedcontainer 1 houseselectric compression element 2 andcoil spring 3; there isspace 4 as well in the container.Coil spring 3 is engaged at both ends bysnubber 5 protruding fromelectric compression element 2 side and sealedcontainer 1 side; namely,electric compression element 2 is elastically supported bycoil spring 3. - The hermetic electric compressor has been designed to compress the R134a refrigerant, a typical HFC system refrigerant, whose ozone layer destruction factor is zero.
-
FIG. 13 is noise characteristic chart of the conventional hermetic electric compressor, disclosed in thepatent document 1; the lateral axis representing the ⅓ octave frequency, the longitudinal axis the noise level.FIG. 14 details the noise characteristic shown inFIG. 13 ; where, the lateral axis representing the frequency, the longitudinal axis the noise level. -
FIG. 15 shows resonance frequency characteristic of mechanical vibration generated byelectric compression element 2 of the conventional hermetic electric compressor; the lateral axis representing the frequency, the longitudinal axis representing level of the acceleration. - The natural resonance frequency due to mechanical vibration generated by
electric compression element 2 has been measured by running without load a hermetic electric compressor with the power supply frequency varied, and plotting the acceleration level measured onelectric compression element 2, on the frequency axis. The resonance frequency due to mechanical vibration caused byelectric compression element 2 is defined as a range of frequencies where the measured acceleration level (vibration level) reach the highest, including the foot areas of the peak in the higher and the lower frequency regions. -
FIG. 16 shows resonance frequency characteristic ofcoil spring 3, in the state whereelectric compression element 2 is put oncoil spring 3; the lateral axis representing the frequency, the longitudinal axis representing the acceleration level. Also shown in the chart is a cavity resonance frequency formed inspace 4, with R134a used as the refrigerant. - The natural resonance frequency of
coil spring 3 has been measured by running without load a hermetic electric compressor with the power supply frequency varied, and plotting the acceleration level measured on the surface of sealedcontainer 1, on the frequency axis. The resonance frequency ofcoil spring 3 is defined as the range of frequencies where the measured acceleration level (vibration level) reaches the highest, including the foot areas of the peak in the higher and the lower frequency regions. - Now in the following, operation of the above-configured hermetic electric compressor is described.
- When power supply is turned ON,
electric compression element 2 starts its operation of compressing refrigerant gas. Due to changes of loads and other factors during the compression operation,electric compression element 2 generates mechanical vibrations which contain various frequencies. The mechanical vibration should cause big noises and vibrations if it is conveyed direct to sealedcontainer 1. However, since the elasticity ofcoil spring 3 absorbs vibration, the vibration which should have been conveyed to sealedcontainer 1 is attenuated. Thus the noises and vibrations are reduced with the hermetic electric compressors. - In the above-described configuration, however, although the mechanical vibrations generated by
electric compression element 2 can be absorbed by the elasticity ofcoil spring 3, the noises and vibrations increase when resonance frequency of the mechanical vibration and that ofcoil spring 3 coincide, vibration ofcoil spring 3 is enhanced and resonates at the resonance frequency; the enhanced vibration is propagated to sealedcontainer 1 causing noise and vibration of that frequency. Thus the hermetic electric compressors have had the noise and vibration problem. - Now, a practical example is described. Referring to
FIG. 15 andFIG. 16 , peak of resonance frequency of the mechanical vibration generated byelectric compression element 2 resides at the neighborhood of 540 Hz, which approximately coincides with the peak of resonance frequency ofcoil spring 3 mounted withelectric compression element 2. Since resonance frequency of the mechanical vibration and that ofcoil spring 3 are in coincidence, the hermetic electric compressor exhibits a noise peak at 540 Hz, as shown inFIG. 14 . - On top of the above noise, another noise is generated by the following operation.
- Namely, in the conventional hermetic electric compressors, cavity resonance frequency formed in
space 4 within sealedcontainer 1 resides somewhere at the peak, inclusive of its foot areas, of resonance frequency ofcoil spring 3 mounted withelectric compression element 2. - Referring to
FIG. 16 , peak of the resonance frequency ofcoil spring 3 mounted withelectric compression element 2 resides at the vicinity of 550 Hz. Also the cavity resonance frequency formed inspace 4 approximately coincides with the frequency. Furthermore, the hermetic electric compressor has its noise peak in the neighborhood of 550 Hz, as shown inFIG. 14 . - The reason for the above is as follows. The mechanical vibration generated by
electric compression element 2 vibratescoil spring 3 viaupper snubber 5. This creates beating and rubbing betweencoil spring 3 and the upper andlower snubbers 5. The beating and rubbing is applied oncoil spring 3 as vibration energy. Then,coil spring 3 resonates at the inherent resonance frequency ofcoil spring 3 mounted withelectric compression element 2. As the result, noise is generated at the frequency, and the noise vibrates a cavity formed inspace 4 of sealed container at the resonance frequency. Thus the noise with hermetic electric compressors is enhanced. - Furthermore, if cavity resonance frequency formed in
space 4 of sealedcontainer 1 coincides with the peak, including the foot areas, of resonance frequency of mechanical vibration generated byelectric compression element 2 and resonance frequency ofcoil spring 3, resonation ofcoil spring 3 created by the mechanical vibration provides a vibrating effects onspace 4. Thus the noise due to resonation of the cavity is further increased with the conventional hermetic electric compressors. - The present invention offers a hermetic electric compressor which includes a sealed container and a coil spring for elastically supporting an electric compression element housed within the sealed container. In which compressor, resonance frequency of the coil spring mounted with the electric compression element does not coincide with resonance frequency of mechanical vibration caused by the electric compression element, or a cavity resonance frequency formed in a space within the sealed container.
-
FIG. 1 is a cross sectional view of a hermetic electric compressor in accordance with a first exemplary embodiment of the present invention, sectioned vertically. -
FIG. 2 shows a front elevation of a coil spring in the first embodiment. -
FIG. 3 is a resonance frequency characteristic chart of a coil spring in the first embodiment. -
FIG. 4 is a noise characteristic chart, which compares a hermetic electric compressor in the first embodiment and a conventional hermetic electric compressor. -
FIG. 5 is a detailed noise characteristic chart of a closed-type electric compressor in the first embodiment. -
FIG. 6 shows a cross sectional view of a hermetic electric compressor in accordance with a second exemplary embodiment of the present invention. -
FIG. 7 is a resonance frequency characteristic chart of a coil spring used in a hermetic electric compressor in accordance with the second embodiment. -
FIG. 8 is a noise characteristic chart of a hermetic electric compressor in the second embodiment. -
FIG. 9 is a magnified view of a snubber and a coil spring in accordance with a third exemplary embodiment of the present invention. -
FIG. 10 is a resonance frequency chart, used to show how change in the resonance frequency is caused with a coil spring in the third embodiment. -
FIG. 11 shows how a refrigeration unit in accordance with a fourth exemplary embodiment of the present invention is structured. -
FIG. 12 shows a cross sectional view of a conventional hermetic electric compressor, sectioned vertically. -
FIG. 13 is a noise characteristic chart of a conventional hermetic electric compressor. -
FIG. 14 is a detailed noise characteristic chart of a conventional hermetic electric compressor. -
FIG. 15 is a resonance frequency characteristic chart, showing a resonance created by mechanical vibration caused by electric compression element in a conventional hermetic electric compressor. -
FIG. 16 is a resonance frequency characteristic chart of a conventional coil spring. - Exemplary embodiments of the present invention are described in the following, with reference to the drawings. It is not the intention of these embodiments to limit the scope of the present invention. Those constituent portions identical to those of conventional devices are represented by using the same symbols, and detailed description of which portions is eliminated.
-
FIG. 1 shows a cross sectional view, vertically sectioned, of a hermetic electric compressor in accordance with a first exemplary embodiment.FIG. 2 shows a front elevation of a coil spring in the first embodiment. -
FIG. 3 is a resonance frequency characteristic chart ofcoil spring 101 mounted withelectric compression element 2 in the first embodiment; the lateral axis representing frequency, while the longitudinal axis representing acceleration level. Cavity resonance frequency formed inspace 4 is also shown, with two examples where R600a and R134a, respectively, are used as the refrigerant. -
FIG. 4 compares a hermetic electric compressor in the first embodiment and a conventional hermetic electric compressor in the noise characteristic; the lateral axis representing ⅓ octave frequency, while the longitudinal axis representing noise level. Dotted line indicates a hermetic electric compressor in the first embodiment, solid line indicates a conventional hermetic compressor.FIG. 5 shows details of the noise characteristic in the first embodiment shown inFIG. 4 ; the lateral axis representing frequency, while the longitudinal axis representing noise level. - Referring to
FIG. 1 andFIG. 2 , sealedcontainer 1 houseselectric compression element 2 andcoil spring 101, and is provided withspace 4 in the inside. At both ends ofcoil spring 101 aresnubbers 5 inserted thereto; each of the snubbers protruding fromelectric compression element 2 and sealedcontainer 1, respectively. Thus,electric compression element 2 is elastically supported bycoil spring 101. - The pitch of
coil spring 101 in the first embodiment is uneven, as shown inFIG. 2 . It has a wider pitch “a” at the both end portions, and gradually gets narrower to become a narrow pitch “b” at the central portion; namely, it is wound in a coarse pitch at both end portions and the winding gets denser at the central portion, socoil spring 101 is top-bottom symmetry with respect to the center. - Furthermore, a hermetic electric compressor in the first embodiment has been designed for compressing R600a, a representative refrigerant of hydrocarbon system, which is free of chlorine, fluorine, and the global-warming factor is zero.
- Now, operation of the above-configured hermetic electric compressor is described below.
- When power supply is turned ON,
electric compression element 2 starts compressing the refrigerant. As a result of compressing operation,electric compression element 2 causes mechanical vibrations of various frequencies. The level of vibration goes high at the neighborhood of 540 Hz among other frequencies, or the peak resonance frequency with the mechanical vibration. - While the mechanical vibration has its peak in the neighborhood of 540 Hz, the resonance frequency of
coil spring 101 mounted withelectric compression element 2 resides at the neighborhood of 470 Hz, where acceleration level (vibration level) of the mechanical vibration is low. Thus it is not in coincidence with the resonance frequency of mechanical vibration caused byelectric compression element 2. So,coil spring 101 is not driven by the mechanical vibration to create a resonance. Thus, vibration due to resonation ofcoil spring 101 hardly occurs, and noises and vibrations are reduced with a closed-type electric compressor. - Furthermore, since it uses R600a refrigerant, sonic velocity in the first embodiment is higher as compared with that when R134a refrigerant is used. As the result, a cavity resonance frequency formed in
space 4 of sealedcontainer 1 shifts high to the neighborhood of 700 Hz, from the neighborhood of 540 Hz. The sonic velocity with a refrigerant gas changes also in accordance with a change in the temperature or the pressure of the refrigerant, as indicated in (formula 1); and the resultant shift in the cavity resonance frequency is normally several tens of Hz. So, even after the shift in resonance frequency is taken place, the peak, inclusive of the foot areas, ofcoil spring 101's resonance frequency is residing sufficiently away from the cavity resonance frequency, as seen inFIG. 3 . - A vibration due to resonation of
coil spring 101 hardly occurs, and a gaseous column formed inspace 4 of sealed container is hardly put into resonation. Thus, resonating sound of cavity is reduced. Therefore, the noise can be further lowered with a hermetic electric compressor. - Results of experiments conducted on the above-described uneven-pitched coil spring confirmed that, as seen in
FIG. 3 , peak level of the resonance frequency ofcoil spring 101 mounted withelectric compression element 2 became low and the resonance frequency shifted to as low as the neighborhood of 470 Hz, while it maintained the elastic modulus at the same level as that of conventional even-pitchedcoil spring 3. - It has been generally known that the peak level of
coil spring 101's inherent resonance frequency goes low when the winding pitch is made to be uneven. In addition to the known phenomenon, it is inferred that in a coil spring wound at an uneven pitch the elastic modulus becomes uneven with respect to an amount of displacement. So, the vibration wave structure of condensation and rarefaction incoil spring 101 is broken, and resonance frequency goes low. - In the present invention, ratio of pitch a to pitch b was decided to be; pitch a: pitch b=(1.09-1.60):1. As the result, peak level of
coil spring 101's resonance frequency has been lowered, while the elastic modulus was kept at the comparable level as that of conventional even-pitchedcoil spring 3. If the value of pitch a against pitch b is in excess of 1.60, the difference of spring constant withincoil spring 101 becomes too large, and the amount of displacement grows big in the neighborhood of pitch b, where the spring constant is small. So, there would be a possibility that the spring wires get in direct contact to each other at the neighborhood of pitch b, andcoil spring 101 would get broken due to vibration of compressor or other factors. If the value of pitch a against pitch b is smaller than 1.09, uneven-pitchedcoil spring 101's advantage in the noise reduction is diminished in relation to even-pitchedcoil spring 3. - Although the ratio is decided to be; pitch a: pitch b=(1.09-1.60):1 in the present invention, more preferably it should be pitch a: pitch b=(1.15-1.40):1. By so doing, the above-mentioned possibility of breakage with a coil spring can be avoided even when there is a 2-3% dimensional dispersion in the manufacturing process. Thus the present invention offers a closed-type electric compressor that provides a greater advantage in the noise reduction.
- Relationship among a cavity resonance frequency f1 formed in
space 4 within sealedcontainer 1, sonic velocity V with refrigerant gas and length L ofspace 4 is represented in (formula 1). - The relationship among resonance frequency f2 of
coil spring 101, wire diameter d ofcoil spring 101, effective number of turns Na and inner diameter D is represented in (formula 2). - Even when R134a refrigerant is used in the first embodiment, the peak, inclusive of the foot areas, of resonance frequency of
coil spring 101 mounted withelectric compression element 2 is sufficiently away from the cavity resonance frequency formed inspace 4 within sealedcontainer 1, as seen inFIG. 3 . Therefore, the resonation sound of cavity is suppressed. - There is another approach for avoiding the coincidence of resonance frequencies between
coil spring 3 mounted withelectric compression element 2 and a cavity formed inspace 4, whose resonance frequency is determined depending on the size of sealedcontainer 1 as indicated in (formula 1). That is changing the cavity resonance frequency formed inspace 4. However, modifying the size of a sealedcontainer 1 is not an easy assignment because it leads to not only design modification of a hermetic electric compressor itself but it also makes it unavoidable to extensively re-design refrigeration unit of refrigerators, automatic vending machines, etc. - In the first embodiment of the present invention, however, the coincidence in resonance frequency with a cavity formed in
space 4 of sealedcontainer 1 can be avoided through a simple modification ofcoil spring 101 alone. Thus the low noise-level design can be implemented easily. - As the general principle shown in (formula 2), the resonance frequency of
coil spring 101 can be lowered by either making wire diameter d smaller, increasing effective number of turns Na or increasing inner diameter D. However, this invites a lowered elastic modulus. Then,coil spring 101 shrinks a great deal due to the weight ofelectric compression element 2, which leads to an unwanted mechanical contact ofelectric compression element 2 with sealedcontainer 1 and generation of abnormal sounds. If the wire diameter d is thinned, stress increases to a deteriorated reliability. If the effective number of turns Na is increased, total length ofcoil spring 101 increases, which leads to an increased overall height of sealedcontainer 1, and a problem of oversized hermetic electric compressor arises. - On the other hand, if
coil spring 101's resonance frequency is to be made higher, wire diameter d may be increased, effective number of turns Na may be decreased or inner diameter D may be made to be smaller. However, this invites an increased elastic modulus, so the amount of mechanical vibration generated byelectric compression element 2 that can be absorbed by the coil spring decreases, while the amount of vibration conveyed to sealedcontainer 1 increases, which creates a problem of increased noises and vibrations with a hermetic electric compressor. - However, uneven-pitched
coil spring 101 used in the first embodiment can lower the resonance frequency without sacrificing the elastic modulus and the reliability. Therefore, the problem of abnormal sounds due to mechanical contact betweenelectric compression element 2 and sealedcontainer 1 caused by a lowered elastic modulus and the problem of a deteriorated reliability due to the increased stress are avoidable. The problem of oversized hermetic electric compressor due to the increased length ofcoil spring 101 can also be avoided. Furthermore, the problem of increasing noises and vibrations with a hermetic electric compressor due to the increased elastic modulus ofcoil spring 101 can be avoided either. - Furthermore, since
coil spring 101 has been wound to have a top-bottom symmetry in the coiling pitch, the operation of coupling withsnubber 5 can be performed regardless of the top-bottom orientation ofcoil spring 101. This is another advantage in the assembly of hermetic electric compressors. -
FIG. 6 shows cross sectional view of a hermetic electric compressor in accordance with a second exemplary embodiment. - Being different from
coil spring 101 in the first embodiment,coil spring 24 in the second embodiment has a lowered elastic modulus. -
FIG. 7 is a resonance frequency characteristic chart ofcoil spring 24 mounted withelectric compression element 2 of a hermetic electric compressor in accordance with second embodiment; the lateral axis representing frequency, while the longitudinal axis representing acceleration level. A cavity resonance frequency formed inspace 4 is also shown in the chart. -
FIG. 8 shows measured noise level of a hermetic electric compressor in the second embodiment; the lateral axis representing frequency, while the longitudinal axis representing noise level. - Referring to
FIG. 6 , sealedcontainer 1 houseselectric compression element 2 andcoil spring 24, and is provided withspace 4 inside the container. At both ends ofcoil spring 24 aresnubbers 5 inserted thereto; each of the snubbers is protruding fromelectric compression element 2 and sealedcontainer 1, respectively.Electric compression element 2 is thus supported elastically bycoil spring 24. - Defining sonic velocity within
space 4 in sealedcontainer 1 as V, a cavity resonance frequency formed inspace 4 is inversely proportional to length L ofspace 4 of sealedcontainer 1, as exhibited in (formula 1). -
FIG. 7 shows inherent resonance frequency ofcoil spring 24 mounted withelectric compression element 2. The chart has been provided by running without load the hermetic electric compressor varying the operation frequency, and plotting the vibration level measured on the surface of sealedcontainer 1 on the frequency axis. - Resonance frequency of
coil spring 24 mounted withelectric compression element 2 is defined, based on the results made available by the above measurement, as the range of peak frequency, where the vibration level reaches the highest, including the foot areas at both the higher and the lower frequency regions. The resonance frequency in the present example has the foot area of approximately 50 Hz in both the higher and the lower frequency regions. - Sonic velocity with a refrigerant shifts depending on the changes in temperature and pressure, which shift affects the a cavity resonance frequency formed in
space 4 of sealedcontainer 1. Resultant change in the resonance frequency is a fluctuation of several tens of Hz. - In the present second embodiment,
coil spring 24 having a lowered elastic modulus is employed so that the peak ofcoil spring 24's resonance frequency is raised to be higher than that of the cavity by approximately 200 Hz. Thereby, it would not coincide with a cavity resonance frequency. - Now in the following, operation of the above-configured hermetic electric compressor is described.
- Mechanical vibration caused by
electric compression element 2 vibratescoil spring 24 viasnubber 5. This creates beating and rubbing with the upper and thelower snubbers 5. The beating and rubbing are applied oncoil spring 24 as a vibrating energy.Coil spring 24 resonates at the inherent resonance frequency ofcoil spring 24 mounted withelectric compression element 2. This creates a noise of the above frequency. - The noise is conveyed to
space 4 of sealedcontainer 1. However, since the peak frequency is higher by 200 Hz than cavity resonance frequency formed inspace 4, it is totally out of the scope of resonance frequency range including foot area of approximately 50Hz existing in both the higher and the lower frequency regions, taking the fluctuation of several tens of Hz in the cavity resonance frequency into consideration. Therefore, the noise would not excite the cavity resonance, and travels alongspace 4 within sealedcontainer 1 and reaches sealedcontainer 1 after being attenuated. - Thus, a cavity formed in
space 4 of sealed container has no source of vibration for resonation, and a hermetic electric compressor of reduced cavity resonance sound is offered. - Furthermore, in the present second embodiment,
coil spring 24 of lower elastic modulus is used for making the inherent resonance frequency ofcoil spring 24 mounted withelectric compression element 2 to be different from a cavity's resonance frequency. As the result,coil spring 24 absorbs more amount of mechanical vibration caused byelectric compression element 2, as compared with a case wherecoil spring 24 of higher elastic modulus is used. So, the vibration conveyed to sealedcontainer 1 is significantly attenuated, and vibrations and noises with a hermetic electric compressor are reduced further. Thus, the present invention offers a hermetic electric compressor whose vibration is low and the noise is also low. - There is another approach for avoiding the coincidence of resonance frequencies between
coil spring 24 mounted withelectric compression element 2 and a cavity formed inspace 4, whose resonance frequency is determined depending on kind of refrigerant and the size of sealedcontainer 1. That is changing the cavity resonance frequency formed inspace 4. However, employing a different refrigerant or modifying the size of sealedcontainer 1 is not an easy assignment because it leads to not only design modification of a hermetic electric compressor itself but it also makes it unavoidable to extensively re-design refrigeration unit of refrigerators, automatic vending machines, etc. - In the present second embodiment, however, the coincidence in resonance frequency with a cavity formed in
space 4 of sealedcontainer 1 can be avoided through a simple modification ofcoil spring 24 alone. Thus the low noise-level design can be implemented easily. - Furthermore, there are various designing models for a hermetic electric compressor, which employ sealed
container 1 of different sizes, different kinds of refrigerant gas, different electric compression elements of different weights, etc. For each of such models, the structure of no-coincidence with a cavity resonance frequency formed inspace 4 of sealedcontainer 1 can be realized by simply changingcoil spring 24 alone. Thus, a low-noise design can be implemented with ease in accordance with the present invention. -
FIG. 9 is a magnified cross sectional view ofsnubber 25 andcoil spring 124 in a third exemplary embodiment. -
FIG. 10 is a resonance frequency characteristic chart, which shows results of measurement on relationship between contacting length ofsnubber 25 with inner diameter ofcoil spring 124 and the resonance frequency, and a cavity resonance frequency formed inspace 4 within sealedcontainer 1; the lateral axis representing contacting length ofsnubber 25 with inner diameter ofcoil spring 124, the longitudinal axis representing resonance frequency. - Referring to
FIG. 9 ,snubber 25 in the present third embodiment, which is basically the same as that used in a hermetic electric compressor in the first embodiment, has a shorter length in itsstraight appearance portion 25 a, so that the length ofsnubber 25 having contact with inner diameter ofcoil spring 124 becomes shorter. - In
FIG. 10 , lengths ofsnub bar 25 having contact with inner diameter ofcoil spring 124 have been provided by changing the length ofstraight appearance portion 25 a ofsnubber 25. Resonance frequency was measured for the varied lengths. The shorter the length ofstraight appearance portion 25 a, the higher the resonance frequency withcoil spring 124. In the present third embodiment, resonance frequency ofcoil spring 124 has been set to be higher than that of cavity by 100 Hz. - Operation of the above-configured hermetic electric compressor is described below.
- The resonance frequency of
coil spring 124 mounted withelectric compression element 2 has been set at a point which is higher by 100 Hz than that of a cavity formed inspace 4 of sealedcontainer 1, by reducing the contacting length ofstraight appearance portion 25 a with inner diameter ofcoil spring 124. - Consequently, the sound created by resonance frequency of
coil spring 124 mounted withelectric compression element 2 does not excite a cavity resonance frequency formed inspace 4 within sealedcontainer 1, but it travels alongspace 4 of sealedcontainer 1 and reaches sealedcontainer 1 after being attenuated. Thus the noise with hermetic electric compressor has been reduced. - There is another approach for avoiding the coincidence of resonance frequencies between
coil spring 124 mounted withelectric compression element 2 and a cavity formed inspace 4, whose resonance frequency is determined depending on kind of refrigerant and the size of sealedcontainer 1. That is changing the cavity resonance frequency formed inspace 4. However, employing a different refrigerant or modifying the size of sealedcontainer 1 is not an easy assignment because it leads to not only design modification of a hermetic electric compressor itself but it also makes it unavoidable to extensively re-design refrigeration unit of refrigerators, automatic vending machines, etc. - In the present third embodiment, however, the coincidence of
coil spring 124's resonance frequency with that of a cavity formed inspace 4 of sealedcontainer 1 can be avoided through a simple modification oflower snubber 25 in itsstraight appearance portion 25 a alone. Thus, the cavity formed inspace 4 of sealedcontainer 1 has no source of vibration for resonation, and a hermetic electric compressor of low cavity resonance sound is offered. - Furthermore, there are various designing models for a hermetic electric compressor, which employ sealed
container 1 of different sizes, different kinds of refrigerant gas, different electric compression elements of different weights, etc. For each of such models, the structure of no-coincidence with cavity resonance frequency formed inspace 4 of sealedcontainer 1 can be realized by simply changingcoil spring 124 alone. Thus, a low-noise design can be implemented with ease in accordance with the present invention. -
FIG. 11 shows a structure of a refrigeration unit in accordance with a fourth exemplary embodiment. - Referring to
FIG. 11 ,compressor 11,condenser 12,expansion device 13, drier 14 andevaporator 15 are coupled by means of piping for allowing a fluid to circulate. - Operation of the above-configured refrigeration unit is described below.
- As to the noises originating from
compressor 11, in addition to those radiated to outside direct fromcompressor 11, some are propagated through the inside of the piping to other elements constituting the refrigeration unit, which have been coupled together by the piping. These noises are conveyed toevaporator 15 side, in which the pressure pulsating of refrigerant gas is small, and reverberate in the spacious inside ofevaporator 15. The sound at evaporator is discharged direct toward outside. However, sincecompressor 11 has a low cavity resonating sound, the noises originating fromcompressor 11 and propagating toevaporator 15 via the inside of piping are small. Thus, a low-noise refrigeration unit is offered. - A hermetic electric compressor in the present invention reduces the creation of a resonation by coincidence of coil spring resonance frequency and resonance frequency of mechanical vibration. Thus, a low-noise and low-vibration configuration is implemented for the hermetic electric compressors.
- A hermetic electric compressor in the present invention reduces the creation of a resonation by coincidence of coil spring resonance frequency and cavity resonance frequency formed in the space. Thus, a low-nose and low-vibration configuration is implemented for the hermetic electric compressors.
- Creation of a resonation with a coil spring due to mechanical vibration caused by an electric compression element can be avoided in a hermetic electric compressor in accordance with the present invention, and the resultant noises and vibrations are reduced. Therefore, the compressor can be used also in a refrigeration showcase, a dehumidifying apparatus, etc.
- Reference Numerals in the Drawings
-
- 1 Sealed container
- 2 Electric compression element
- 3,24,101,124 Coil spring
- 4 Space
- 5,25 Snubber
Claims (19)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
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JP2002318197 | 2002-10-31 | ||
JP2002-318197 | 2002-10-31 | ||
PCT/JP2003/013892 WO2004040136A1 (en) | 2002-10-31 | 2003-10-30 | Sealed type motorized compressor and refrigerating device |
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US7249937B2 US7249937B2 (en) | 2007-07-31 |
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US10/498,476 Active 2025-02-23 US7249937B2 (en) | 2002-10-31 | 2003-10-30 | Hermetic electric compressor and refrigeration unit including non-resonating support structure for the compressor |
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US (1) | US7249937B2 (en) |
EP (1) | EP1580428B1 (en) |
KR (1) | KR100563288B1 (en) |
CN (1) | CN100371592C (en) |
AU (1) | AU2003280623A1 (en) |
DE (1) | DE60312387T2 (en) |
WO (1) | WO2004040136A1 (en) |
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WO2012126074A1 (en) * | 2011-03-18 | 2012-09-27 | Whirlpool S.A. | Suspension spring for a refrigeration compressor |
WO2017137328A1 (en) | 2016-02-09 | 2017-08-17 | Arcelik Anonim Sirketi | A compressor that is operated in a silent manner |
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Also Published As
Publication number | Publication date |
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EP1580428A1 (en) | 2005-09-28 |
KR20040077675A (en) | 2004-09-06 |
EP1580428B1 (en) | 2007-03-07 |
DE60312387D1 (en) | 2007-04-19 |
AU2003280623A1 (en) | 2004-05-25 |
DE60312387T2 (en) | 2007-11-08 |
EP1580428A4 (en) | 2005-09-28 |
CN100371592C (en) | 2008-02-27 |
CN1685153A (en) | 2005-10-19 |
US7249937B2 (en) | 2007-07-31 |
KR100563288B1 (en) | 2006-03-27 |
WO2004040136A1 (en) | 2004-05-13 |
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